Detachable drill bit shank slotting device



C. E. COOK.

May 23, 1939.

DETACHABLE DRILL BI'T SHANK SLOTTING DEVICE' Filed Sept. 23, 1957 A35".A 3. A m 2 l x v v v N M 9 8 1 6 A: A; r

[LEnEUDK v Patented May 23, 1939 UNITED STATES PATENT OFFICE 1 2,159,840DETACHABLE DRILL BIT SHANK SLOTTING DEVICE Charles Edward Cook, SouthPorcupine, Ontario, Canada, assignor to International Detachable Bits &Equipment, Limited, Timmins, Ontario, Canada, a corporation of Ontario,Canada Application September 23, 1937, Serial No. 165,239

1 Claim. (Cl. 76-95) tail cross-section in the shank end solely by ingapplication Serial No. 165,238 filed September 23, 1937, Methods offorming detachable drill bit shanks. My device is designed to forge thestraight walled slot in the shank end into a slot of dovetailcross-section whichis the ultimate form it assumes, solely by a forgingoperation.

With the above and other objects in view which will hereinafter appearas the specification proceeds, my invention consists, inits preferredembodiment, of the construction and'arrangement all as hereinafterdescribed and illustrated in the accompanying drawing in which:

Fig. 1 represents a vertical section through my device showing thedetachable drill bit shank in position therein ready to be dollied andthe device mounted in a drill steel sharpener.

Fig. 2 is a similar view to Fig. 1 only showing the shank end providedwith the straight walled slot illustrated in Fig. 1 dollied into one ofdovetail cross-section by my device.

Fig. 3 is a vertical cross-section through line 3-3 (Fig. 2).

Fig. 4 is a vertical cross-section through the the , line 44 (Fig. 2).

Fig. 5 is a perspective detail of my dolly, and

Fig. 6 is a plan view ofthe shank end showing the removable head of thedolly applied thereto but partially detached therefrom.

Like characters of reference indicate corresponding parts in thedifferent views of the draw- My device comprises a divided clamping diehaving a lower or stationary portion l adapted to be mounted upon thelower die block 2 of a drill steel sharpener, and an upper or verticallymovable portion 3 adapted to be mounted on the ram 4 of the drill steelsharpener and to coact with the portion I for clamping the detachabledrill bit shank A in position therebetween.

The interior of the divided die is enlarged at one end to receive theenlarged end of the shank. When such shank is in position in theclamping die its end is dollied by a dolly 5 adapted to be mounted inthe dollying attachment (not shown) 01 the drill steel sharpener.

The dolly 5 has a cylindrical bore 6 extending axially from its endwhich receives the removable cylindrical head I. The end face of thehead is provided with a diametrically extending rib 8 of dovetailcross-section of the form of the slot in the shank end it is designed toforge.

Upon the heated detachable drill bit shank A (which has had previously adiametrical straight walled slot 9 forged in the end thereof, forinstance, by a dollying operation such as described in the abovementioned co-pending application) being clamped between the portions land 3 of the clamping die and the dolly 5 being aligned with itslongitudinal. axis coincident with the longitudinal axis of the shank A,the dollying attachment is actuated with the result that thereciprocation of the dolly 5 causes its head 6 to impart a dollyingaction upon the end of such shank swaging such end so that the straightwalled slot 9 therein is forged into a slot Ill of dovetailcross-section conforming with the shape of the rib 8 which has beeninitially inserted into the slot 9. 1

When the dollying operation is complete the dolly 5 is withdrawn leavingthe head 6 attached to the shank. The ram 4 is then retracted and theshank with the head 6 attached is removed from the clamping die. Bymeans of a hammer the head is then tapped transversely with respect tothe shank as illustrated in Fig. 6 wherein the rib 8 is detached fromthe slot ll) of dovetail cross-section formed in the shank end by thedollying operation.

The shank A is now ready foruse without the necessity of any machiningwhatsoever and the detachable bit may be attached thereto.

From the description it will be apparent that I have originated a devicewhich will forge the shank end into the ultimte form necessary for itsconnection to the detachable bit.

Although I have described and shown my device as of. the form suitablefor forging the end of the shank into the required shape for. connectionto a detachable bit of the specific construction described in UnitedStates Patent No. 2,030,576, issued February 11, 1936, it will beunderstood that by varying the configuration of the end of the head 6 mydevice may be used for forging the end of the shank to receivedetachable bits of other constructions.

By the use of my-device any machining, milling or other operationsentailing a removal of metal from the shank, the employment of specialmachines and consequent highly skilled labour, are avoided as the shankend is formed by my device in a standard drill steel sharpener entirelyby a forging operation.

Such device is equally applicable for forging the ends of new shanks orfor reconditioning worn or damaged shanks which have been previouslyused.

What I claim as my invention is:

. CHARLES EDWARD COOK.

